Alginic acid is a natural polysaccharide extracted from seaweed.

He is interested in ancient mathematics.

He crossed the river in a sampan.

Oleic acid is abundant in olive oil.

He is working as the chief of staff of the army.

He strongly encourages young people's participation in politics.

He strongly encourages young people to actively participate in politics.

Glutamic acid is one of the components of proteins.

My birthday is on the twenty-third.

Climbing the mountain road is tough, but the view from the top is worth it.